Re: Are depleted glycogen stores replenished in Ketosis?

Hello Mighty,

Glycogen is basically the storage form of glucose stored in the Liver and to some extent within the muscles: it is classified as the main fuel of the body while eating and especially for the Brain.

At the beginning of a fast, you will burn glycogen, fat, and some protein (protein-sparing) for energy.
After about two weeks, you burn mainly fat, so the process is one from glucose-burning as our primary fuel-source while eating, to one of fat-burning or ketosis while not eating; ketones from fat-burning then become our main fuel supply once glucose stores are depleted.
It is only when the fast is broken that these reserves are replaced, and that includes the glycogen stores of the Liver and of the muscles, which overall lose about 50% of their glycogen (not to be confused with protein).

Glycogen stores are not replenished during a fast as the body only requires minimal amounts of glucose to feed the Brain and other functions.

In other words, this Stephen H Buhner is largely incorrect, except for the point where you quoted...........

"the body continues to metabolize fairly small amounts of protein (protein-sparing) during a fast to obtain the minimally necessary glucose for functions that ketones cannot perform?"

Chrisb1